This invention relates to solid electrolyte fuel cells and assemblies of such cells for directly converting chemical energy into electricity.
High temperature fuel cells employing a solid electrolyte and oxidizing a gaseous fuel are known. Typically, such cells and assemblies operate at temperatures ranging from about 700.degree. to 1100.degree. C. In a typical cell, oxygen from air is reacted with a fuel to produce electrical energy, heat, water vapor and oxides of carbon. These relatively high temperature fuel cells convert fuel to electricity more efficiently than heat engines or lower temperature fuel cells. The fuel cell assemblies are compact, simple in design, noiseless, produce little environmental pollution, lack moving parts and are potentially highly reliable.
In spite of these advantages, no high temperature fuel cell assembly has yet become commercially acceptable. Known fuel cells employ materials that are relatively expensive and very difficult to fabricate in the complex configurations that are required in the known designs. Therefore the costs of materials and the fabrication of those materials have been a significant factor in delaying commercial acceptance of fuel cells. In addition, in known fuel cell assemblies, it is very difficult to keep seals intact that prevent unwanted mix of air and fuel.
Accordingly, it is desirable to provide improved fuel cells and fuel cell assemblies that incorporate the advantages of known cells and assemblies, but which are inexpensive to produce, reliable and efficient.